Over the last 25 years, outbreaks of spruce bark beetles have killed trees across more than a million acres of forests on Alaska’s Kenai Peninsula, southwest of Anchorage. But people living in the area are losing a sense of just how bad the environmental damage caused by these insects has been, according to new research.

The study, led by University of Missouri sociologist Hua Qin, is unusual because it tracks the evolution of people’s perceptions of insect-related forest damage, rather than capturing them at only one point in time. Over the course of just four years, people’s perceptions of the severity of the beetle damage decreased, the study found.

In 2004, Qin and his colleagues collected data from a mail survey of 1,088 households in six communities around the Kenai Peninsula. The researchers asked people to describe how much of the local forest had been lost to beetle outbreaks and assess how worried they were about consequences like wildfires, danger from falling trees, loss of scenic views, decline of property values, and soil erosion. In 2008, they surveyed 766 households in these same communities, including 433 that participated in the original study.

The risk of wildfires involving dead trees or invasive grasses in degraded forest areas remained prominent in people’s minds, the researchers report in the journal Human Ecology. This may be because significant wildfires occurred in the area in 2005 and 2007. These results illustrate “social amplification of risk,” a concept that describes the tendency for people to perceive greater risks from a phenomenon when they’ve experienced it directly.

The researchers also compiled data from aerial surveys of the Kenai Peninsula measuring the percentage of trees killed by spruce bark beetles. In some areas, such as around Ninilchik, Anchor Point, and Homer, over 90 percent of trees had died. Between 2004 and 2008, there was little natural regrowth and the percentage of dead trees didn’t change much.

But survey respondents perceived the beetle damage as less severe in 2008 than they had in 2004. That is, people’s perceptions of environmental conditions improved over time, even though conditions didn’t change much in reality.

The researchers say this aspect of the results reflects the “issue-attention cycle,” an idea put forth by the economist Anthony Downs in the early 1970s to explain why public policy issues tend to fade from people’s attention after a period of time, even if the problem itself has not been solved.

The decline in the perceived severity of beetle damage is also consistent with the idea of “shifting baselines,” wherein people come to see degraded environmental conditions as normal. Often, we think of shifting baselines as happening over generational time scales: kids today don’t know what nature was like when granddad was growing up. The new study shows how shifting baselines can also occur on an individual level, and within a surprisingly short amount of time.

Lately, there’s a lot of talk about “adaptation,” especially relating to climate change – how will we learn to live in a radically altered world? But perhaps in a psychological sense at least, we humans tend to adapt more readily than we should. – Sarah DeWeerdt | 21 April 2015